- FORCE (F) acting over a straight line DISTANCE (d).
W=Fd - MOMENT of force (M) acting over an arc (of length r) whose center is an axis of rotation
W=Mr In either case, work is measured in units like foot*lbs. or N*m.

E=Mr for work around an axis of rotation

Power's SI unit of measurement is the Watt, representing the generation or absorption of energy at the rate of 1 Joule/sec. Power's unit of measurement in the English system is the horsepower, which is equivalent to 735.7 Watts.

## For translational motions: | ## for rotational motions: |
---|---|

## P = Fd/t | ## P = Mr/t |

If, in the equation for rotational motion, which includes motion around a joint axis, we substitute:

so that JOINT POWER is the product of:

- M (joint moment) and
- w (joint angular velocity.)

More on JOINT POWER